Methods and apparatus for adjusting frequency and/or PWM-based sensors

ABSTRACT

A sensor module adjustment circuit includes a device have a position between minimum and maximum positions. First and second position sensors sense the position of the device and generate first and second position values, respectively. A sensor module includes first and second signal conversion modules that generate first and second signal waveforms based on the first and second position values, that include first and second gain modules, and that vary a frequency and a duty cycle, respectively, of the first and second signal waveforms based on the first and second position values. A gain magnitude module determines first and second signal gains of the first and second gain modules, respectively. A signal preset module adjusts the first and second signal gains so that the first and second signal waveforms are equal to first and second predetermined signal waveforms, respectively, when the position of the device is fixed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/491,903, filed on Aug. 1, 2003, 60/491,700, filed on Aug. 1, 2003,and 60/491,905, filed on Aug. 1, 2003, which are hereby incorporated byreference in their entirety.

FIELD OF THE INVENTION

The present invention relates to vehicle control systems, and moreparticularly to sensor modules for redundant position sensing of devicesin vehicle control systems.

BACKGROUND OF THE INVENTION

Vehicle manufacturers are increasingly replacing mechanical linkages invehicles with sensors and electromechanical devices to reduce weight andcost. For example, sensors are replacing mechanical linkages to detectpositions of user operated devices such as accelerator, clutch, andbrake pedals. Signals are transmitted from the sensors to controllersand/or electromechanical devices in the vehicle. For example, a signalfrom an accelerator pedal may be transmitted to an actuator in theelectronic throttle body to adjust the position of the throttle blade.Additionally, a throttle position sensor detects the position of thethrottle blade and transmits a signal to an engine control module.

In cases where mechanical linkages are at least partially eliminated,multiple sensors are commonly used to perform redundant measurements andensure system accuracy. For example, some manufacturers use analogposition sensors that are based on a resistive ink or paste that isdeposited on a non-conducting substrate. Other manufacturers useapplication specific integrated circuits (ASICs) in combination withsensors. The sensors typically include hall effect or inductivelycoupled sensors. The ASICs receive analog signals from the sensors andoutput pulse width modulated (PWM) or other types of signals. Any ofthese sensors may use one or multiple shared reference voltages.However, as the number of sensors increases, the number of wires andoverall cost increases.

SUMMARY OF THE INVENTION

A sensor module adjustment circuit according to the present inventionincludes a device having a position between minimum and maximumpositions. First and second position sensors sense the position of thedevice and generate first and second position values, respectively. Asensor module includes a first signal conversion module that generates afirst signal waveform based on the first position value, that varies afrequency of the first signal waveform based on the first positionvalue, and that includes a first gain module. A second signal conversionmodule generates a second signal waveform based on the second positionvalue, varies a duty cycle of the second signal waveform based on thesecond position value, and includes a second gain module. A gainmagnitude module communicates with the first and second gain modules anddetermines first and second signal gains of the first and second gainmodules, respectively. A signal preset module communicates with the gainmagnitude module and adjusts the first and second signal gains so thatthe first and second signal waveforms are equal to first and secondpredetermined signal waveforms, respectively, when the position of thedevice is fixed.

In other features, the sensor module further includes a signal combinerthat communicates with the first and second signal conversion modules,that receives the first and second signal waveforms, and that generatesa single signal waveform based on the first and second signal waveforms.A frequency of the single signal waveform corresponds with the frequencyof the first signal waveform and a duty cycle of the single signalwaveform corresponds with the duty cycle of the second signal waveform.A system comprises the sensor module adjustment circuit and a conductorhaving a first end that communicates with the signal combiner and asecond end. A control module communicates with the second end of theconductor. The signal combiner transmits the single signal waveform tothe control module on the conductor and the control module decodes thesingle signal waveform to determine the first and second positionvalues.

In still other features of the invention, the control module scales thefirst and second position values between position values that correspondto the first and second predetermined signal waveforms and a positionvalue that is learned during normal operations to determine the positionof the device. The control module converts the position of the deviceinto a normalized value that represents a fraction of a range betweenthe minimum and maximum positions of the device. The device is athrottle blade of a vehicle. The control module determines thenormalized value based on a measured position value, position valuesthat correspond to the first and second predetermined signal waveforms,a learned minimum position value, a maximum airflow position value, abreakout position value, and/or a breakout displacement value.

In yet other features, a system comprises the sensor module adjustmentcircuit and a first conductor having a first end that communicates withthe first signal conversion module and a second end. A second conductorhas a first end that communicates with the second signal conversionmodule and a second end. A control module communicates with the secondends of the first and second conductors. The first and second signalconversion modules transmit the first and second signal waveforms,respectively, to the control module on the first and second conductors.The control module decodes the first and second signal waveforms todetermine the first and second position values. The control modulescales the first and second position values between position values thatcorrespond to the first and second predetermined signal waveforms and aposition value that is learned during normal operations to determine theposition of the device.

In still other features of the invention, the control module convertsthe position of the device into a normalized value that represents afraction of a range between the minimum and maximum positions of thedevice. The device is a throttle blade of a vehicle. The control moduledetermines the normalized value based on a measured position value,position values that correspond to the first and second predeterminedsignal waveforms, a learned minimum position value, a maximum airflowposition value, a breakout position value, and/or a breakoutdisplacement value.

In yet other features, the device is a throttle blade of a vehicle. Theposition of the throttle blade is fixed at one of a maximum airflowposition, a breakout position, a minimum stop throttle position, or adefault throttle position while the signal preset module adjusts thefirst and second signal gains. The gain adjustment module includes trimresistors. A resistance of the trim resistors determines the first andsecond signal gains. The signal preset module is a resistor trimmingmodule that adjusts the resistance. The device is one of an acceleratorpedal, a brake pedal, a clutch pedal, or a throttle blade of a vehicle.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a functional block diagram of a vehicle control systemincluding a control module that receives signals from vehicle sensorsaccording to the present invention;

FIG. 2 is a functional block diagram of a sensor module adjustmentcircuit including a sensor module that converts first and secondposition values into variable frequency and variable duty cycle signalwaveforms;

FIG. 3 is a functional block diagram of a sensor module adjustmentcircuit including a sensor module that converts first and secondposition values into a single signal waveform;

FIG. 4 is a graph showing throttle displacement percentage as a functionof measured throttle position when the sensor module is preset with thethrottle blade in a breakout position;

FIG. 5 is a flowchart illustrating steps performed by the sensor moduleand the control module during a sensor module preset operation; and

FIG. 6 is a flowchart illustrating steps performed by the control moduleto convert position values into throttle displacement percentages.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses. For purposes of clarity, the same referencenumbers will be used in the drawings to identify similar elements. Asused herein, the term module refers to an application specificintegrated circuit (ASIC), an electronic circuit, a processor (shared,dedicated, or group) and memory that execute one or more software orfirmware programs, a combinational logic circuit, a micro-controllerwith timer I/O, and/or other suitable components that provide thedescribed functionality.

Referring to FIG. 1, a vehicle 10 includes an engine 12 and a controlmodule 14. The engine 12 includes a cylinder 16 that has a fuel injector18 and a spark plug 20. Although a single cylinder 16 is shown, thoseskilled in the art can appreciate that the engine 12 typically includesmultiple cylinders 16 with associated fuel injectors 18 and spark plugs20. For example, the engine 12 may include 4, 5, 6, 8, 10, 12, or 16cylinders 16.

Air is drawn into an intake manifold 22 of the engine 12 through aninlet 24. A throttle blade 26 regulates air flow through the inlet 24.Fuel and air are combined in the cylinder 16 and are ignited by thespark plug 20. The throttle blade 26 controls the rate that air flowsinto the intake manifold 22. The control module 14 adjusts the rate thatfuel is injected into the cylinder 16 based on the air that is flowinginto the cylinder 16 to control the air/fuel (A/F) ratio within thecylinder 16. The control module 14 communicates with an engine speedsensor 28 that generates an engine speed signal. The control module 14also communicates with mass air flow (MAF) and manifold absolutepressure (MAP) sensors 30 and 32, which generate MAF and MAP signals,respectively.

The engine 12 includes an electronic throttle body (ETB) 34 that isassociated with the throttle blade 26. The ETB 34 is controlled by thecontrol module 14 and/or a dedicated controller such as an electronicthrottle controller (ETC). First and second throttle position sensors 36and 38, respectively, detect a position of the throttle blade 26 in theETB 34 and generate first and second position signals that represent theposition of the throttle blade 26. The first and second position signalsare received by a sensor module 40. For example, the sensor module 40may be an application specific integrated circuit (ASIC). The sensormodule 40 transmits a signal to the control module 14 that is pulsewidth modulated (PWM) and that has a variable frequency as will bedescribed in further detail below.

The vehicle 10 optionally includes first and second accelerator pedal(AP) position sensors 42 and 44, respectively, that detect a position ofthe AP 46. The first and second AP position sensors, 42 and 44,respectively, generate first and second position signals that representthe position of the AP 46. A sensor module 50 receives the first andsecond position signals and transmits a PWM signal to the control module14 that also has a variable frequency.

The vehicle 10 optionally includes first and second brake pedal (BP)position sensors 52 and 54, respectively, that detect a position of theBP 56. The first and second BP position sensors 52 and 54, respectively,generate first and second position signals that represent the positionof the BP 56. A sensor module 58 receives the first and second positionsignals and transmits a PWM signal to the control module 14 that alsohas a variable frequency.

In the case of a manual transmission, the vehicle 10 optionally includesfirst and second clutch pedal (CP) position sensors 60 and 62,respectively, that detect a position of the CP 64. The first and secondCP position sensors 60 and 62, respectively, generate first and secondposition signals that represent the position of the CP 64. A sensormodule 66 receives the first and second position signals and transmits aPWM signal to the control module 14 that also has a variable frequency.Those skilled in the art can appreciate that sensors other than thoseshown in FIG. 1 may be employed.

The sensor modules 40, 50, 58, and 66 generate respective PWM signalsbased on respective first and second position signals. The PWM signalsinclude a single signal waveform that indicates values of both the firstand second position signals. In an exemplary embodiment, a variablefrequency of a PWM signal corresponds to a value of a first positionsignal, and a variable duty cycle of the PWM signal corresponds to avalue of a second position signal. Those skilled in the art canappreciate that any of the sensor modules 40, 50, 58, and/or 66 mayreceive position signals from more than two position sensors for addedredundancy.

It is possible to utilize only the first throttle position sensor 36 andstill obtain redundant measurements of the position of the throttleblade 26. For example, other sensors such as the MAF and MAP sensors 30and 32, respectively, indicate a flow rate and/or a pressure of the airin the intake manifold 22 that may be used to determine a position ofthe throttle blade 26. In this case, the sensor module 40 generates asignal that includes one of a variable frequency and a variable dutycycle that is based on a value of the first position signal from thefirst throttle position sensor 36. However, it is difficult toaccurately compare the position of the throttle blade 26 from the firstthrottle position sensor 36 and from the MAF and/or MAP sensors 30 and32, respectively, in both static and dynamic vehicle conditions.

The control module 14 decodes the PWM signals to determine positionvalues of respective first and second position signals. The controlmodule 14 converts the position values into normalized values thatrepresent a fraction of a range between minimum and maximum positions.For example, a normalized position value for the throttle blade 26 mayrepresent a fraction of the range between an idle throttle position anda wide open throttle (WOT) position.

In this case, a normalized position value of 0% may correspond with theidle throttle position and a normalized position value of 100% maycorrespond with the WOT position. Therefore, the sensor modules 40, 50,58, and 60 are preset to output predetermined PWM signals when positionsof their respective vehicle devices 26, 46, 56, and 64 are fixed. Forexample, sensor module 40 may be preset to output a predetermined signalwaveform when the throttle blade 26 is fixed at a maximum airflowthrottle position. After the sensor module 40 is preset, the controlmodule 14 may scale decoded position values between the preset positionvalue and a position value that is learned during normal operations todetermine a position of the throttle blade 26.

Referring now to FIG. 2, a sensor module adjustment circuit 74 includesthe sensor module 40 and a signal preset module 76. An exemplaryembodiment of the present invention is outlined below with respect toposition sensing of the throttle blade 26. However, analogous operationof the sensor module adjustment circuit 74 is contemplated with respectto position sensing of other vehicle devices including the acceleratorpedal 46, brake pedal 56, and clutch pedal 64.

The sensor module 40 includes a frequency signal conversion module 78and a pulse width modulated (PWM) signal conversion module 80. An inputof the frequency signal conversion module 78 receives the first positionsignal from the first throttle position sensor 36. The frequency signalconversion module 78 generates a first signal waveform 82 based on thefirst position signal. The frequency signal conversion module 78 alsovaries a frequency of the first signal waveform 82 based on the value ofthe first position signal.

An input of the PWM signal conversion module 80 receives the secondposition signal from the second throttle position sensor 38. The PWMsignal conversion module 80 generates a second signal waveform 84 basedon the second position signal. The PWM signal conversion module 80 alsovaries a duty cycle of the second signal waveform 84 based on the valueof the second position signal. The frequency and PWM signal conversionmodules 78 and 80 include first and second gain modules 86 and 88,respectively.

Magnitudes of the first and second signal waveforms 82 and 84 are basedon signal gains of the first and second gain modules 86 and 88,respectively. For example, a frequency of the first signal waveform 82may lower when the signal gain of the first gain module 86 is loweredand while the value of the first position signal remains constant. Thisallows the outputs of the frequency and PWM signal conversion modules 78and 80, respectively, to be preset when a position of the throttle blade26 is fixed.

A gain magnitude module 90 communicates with the first and second gainmodules 86 and 88, respectively, and determines the signal gains of thefirst and second gain modules 86 and 88. For example, the gain magnitudemodule 90 may include trim resistors. In this case, a resistance of thetrim resistors may be adjusted to adjust the signal gains. A single setof trim resistors in the gain magnitude module 90 may determine thesignal gains of the first and second gain modules 86 and 88,respectively.

Alternatively, the gain magnitude module 90 may include separate sets oftrim resistors for the first and second gain modules 86 and 88,respectively. The signal preset module 76 communicates with the gainmagnitude module 90 and adjusts the signal gains. For example, thesignal preset module 76 may be a resistor trimming module that adjusts aresistance of the gain magnitude module 90 to adjust the signal gains.In an exemplary embodiment, the signal preset module 76 employs laserablation techniques to adjust the resistance of trim resistors in thegain magnitude module 90.

Referring now to FIG. 3, the sensor module 40 further includes a signalcombiner 92 that communicates with the frequency and PWM signalconversion modules 78 and 80, respectively. The signal combiner 92generates a single signal waveform 94 based on the first and secondsignal waveforms 82 and 84, respectively. This allows the sensor module40 to transmit values of both the first and second position signals tothe control module 14 on a single conductor.

The signal combiner 92 varies a frequency of the single signal waveform94 based on the value of the first position signal and varies a dutycycle of the single signal waveform 94 based on the value of the secondposition signal. The sensor module 40 is preset before normal operationsby first fixing a position of the throttle blade 26. For example, theposition of the throttle blade 26 may be set to one of a maximum airflowposition, a breakout position, a minimum stop throttle position, or adefault throttle position during a preset operation.

The signal preset module 76 then adjusts the signal gains of the firstand second gain modules 86 and 88, respectively, until the first andsecond signal waveforms 82 and 84, respectively, are equal to first andsecond predetermined signal waveforms for the embodiment illustrated inFIG. 2. The signal preset module 76 adjusts the signal gains until thesingle signal waveform 94 is equal to a predetermined signal waveformfor the embodiment illustrated in FIG. 3.

The control module 14 scales measured position values between positionvalues that corresponds with predetermined signal waveforms and aposition value that is learned during normal operations to determine theposition of the throttle blade 26. For example, the sensor module 40 maybe preset while the throttle blade 26 is fixed in a maximum airflowposition. In this case, the control module 14 may scale a measuredposition value between the maximum airflow position and a minimumposition value that is learned during normal operations to determine theposition of the throttle blade 26. Therefore, the control module 14 doesnot have to determine upper and lower constraints on position valuesbefore or during normal operations.

When a maximum airflow position preset is used, the control module 14may convert the measured position value into a normalized position valuebased on the preset position value, the measured position value, and thelearned position value. When a breakout position preset is used, thecontrol module 14 may convert the measured position value into anormalized position value based on the preset position value, themeasured position value, the learned position value, and thedisplacement of the throttle blade 26 at the preset value. For example,the learned position value may be at a maximum airflow position when thebreakout position preset is used.

Referring now to FIG. 4, the sensor module 40 is preset while thethrottle blade 26 is fixed in a breakout throttle position. Adisplacement function, indicated by 102, indicates displacementpercentages of the throttle blade 26 between the minimum and maximumpositions based on measured position values. An ideal function,illustrated at 104, illustrates displacement percentages between 0% and100% that are directly proportional to measured position values between0 and 100.

To ensure that the measured position values remain between 0 and 100during normal operations, the range of possible measured position valuesis preferably set beyond a range of motion of the throttle blade 26.Therefore, the displacement and ideal functions 102 and 104,respectively, illustrated in FIG. 4 are neither parallel nor collinear.In FIG. 4, measured position values for the throttle blade 26 range froma minimum of 10 to a maximum of 90. The measured position value is equalto 30 while the throttle blade 26 is in the breakout throttle position.

The breakout throttle position also corresponds to a throttledisplacement percentage of 35%. Therefore, the displacement function 102begins at a point defined by a measured position value that is equal to10 and a displacement percentage that is equal to 0%, indicated at 106.The displacement function 102 continues in an approximately linear pathand at a first slope to the measured position value and displacementpercentage value at the breakout throttle position, indicated at 108.The displacement function 102 then continues in an approximately linearpath and at a second slope to a point defined by a measured positionvalue that is equal to 90 and a displacement percentage that is equal to100%, indicated at 110.

Referring now to FIG. 5, a sensor module adjustment algorithm begins instep 118. In step 120, the throttle plate is fixed at a predeterminedposition. In step 122, control reads the first and second signalwaveforms 82 and 84, respectively, or the single signal waveform 94 fromthe sensor module 40. In step 124, control determines the frequency ofthe first signal waveform 82 and the duty cycle of the second signalwaveform 84, or the frequency and the duty cycle of the single signalwaveform 94. In step 126, control converts the frequency to displacementD1 and the duty cycle to displacement D2.

In step 128, control reads D1 and a first desired displacement. In step130, control determines whether the difference between D1 and the firstdesired displacement is less than a first predetermined value. If true,control proceeds to step 132. If false, control proceeds to step 134. Instep 134, the signal preset module 76 adjusts the signal gain of thefirst gain module 86 and control returns to step 128. In step 132,control reads D2 and a second desired displacement. In step 136, controldetermines whether a difference between D2 and the second desireddisplacement is less than a second predetermined value. If true, controlends. If false, control proceeds to step 138. In step 138, the signalpreset module 76 adjusts the signal gain of the second gain module 88and control returns to step 132.

Referring now to FIG. 6, a displacement percentage algorithm begins instep 146. In step 148, the control module 14 converts the first andsecond signal waveforms 82 and 84, respectively, or the single signalwaveform 94 into measured position values. In step 150, control reads ameasured position value, a preset position value, a learned minimumposition value, a maximum position value, a breakout position value, anda breakout displacement percentage. In step 152, control determineswhether the sensor module 40 was preset while the throttle blade 26 wasfixed in a breakout position. If true, control proceeds to step 154. Iffalse, control proceeds to step 156. In step 154, control determineswhether the measured position value is less than the breakout positionvalue. If true, control proceeds to step 158. If false control proceedsto step 160.

In step 160, control computes the normalized displacement value by firstdividing the difference between the measured position value and thepreset position value by the difference between the maximum positionvalue and the preset position value. The quotient is then multiplied bythe difference between 100 and the breakout displacement percentage.Finally, the product is summed with the breakout displacement percentageand control ends. In step 158, control computes the normalized positionvalue by first dividing the difference between the measured positionvalue and the learned minimum position value by the difference betweenthe preset position value and the learned minimum position value.

The quotient is then multiplied by the breakout displacement percentageand control ends. In step 156, control computes the normalized positionvalue by first dividing the difference between the measured positionvalue and the learned minimum position value by the difference betweenthe preset position value and the learned minimum position value. Thequotient is then multiplied by 100 and control ends.

The sensor module adjustment circuit 74 of the present invention allowsfor accurate redundant position sensing of vehicle devices. Bypresetting the sensor module 40 when a position of a device is fixed, anaccurate measure of the position of the device is obtained. Inaccuraciesof position sensors are avoided by scaling the measured position valuesbetween preset position values and position values that are learnedduring normal operations. Therefore, the measured position valuescorrespond more closely with the actual position of the device in thevehicle. Additionally, space usage and cost is decreased by utilizing asingle conductor to transmit dual position indication signals.

Those skilled in the art can now appreciate from the foregoingdescription that the broad teachings of the present invention can beimplemented in a variety of forms. Therefore, while this invention hasbeen described in connection with particular examples thereof, the truescope of the invention should not be so limited since othermodifications will become apparent to the skilled practitioner upon astudy of the drawings, specification, and the following claims.

1. A sensor module adjustment circuit, comprising: a device having aposition between minimum and maximum positions; first and secondposition sensors that sense said position of said device and thatgenerate first and second position values, respectively; a sensor modulethat includes: a first signal conversion module that generates a firstsignal waveform based on said first position value, that varies afrequency of said first signal waveform based on said first positionvalue, and that includes a first gain module; a second signal conversionmodule that generates a second signal waveform based on said secondposition value, that varies a duty cycle of said second signal waveformbased on said second position value, and that includes a second gainmodule; and a gain magnitude module that communicates with said firstand second gain modules and that determines first and second signalgains of said first and second gain modules, respectively; and a signalpreset module that communicates with said gain magnitude module and thatadjusts said first and second signal gains so that said first and secondsignal waveforms are equal to first and second predetermined signalwaveforms, respectively, when said position of said device is fixed. 2.The sensor module adjustment circuit of claim 1 wherein said sensormodule further includes a signal combiner that communicates with saidfirst and second signal conversion modules, that receives said first andsecond signal waveforms, and that generates a single signal waveformbased on said first and second signal waveforms.
 3. The sensor moduleadjustment circuit of claim 2 wherein a frequency of said single signalwaveform corresponds with said frequency of said first signal waveformand a duty cycle of said single signal waveform corresponds with saidduty cycle of said second signal waveform.
 4. The sensor moduleadjustment circuit of claim 1 wherein said device is a throttle blade ofa vehicle and wherein said position of said throttle blade is fixed atone of a maximum airflow position, a breakout position, a minimum stopthrottle position, or a default throttle position while said signalpreset module adjusts said first and second signal gains.
 5. The sensormodule adjustment circuit of claim 1 wherein said device is one of anaccelerator pedal, a brake pedal, a clutch pedal, or a throttle blade ofa vehicle.
 6. The sensor module adjustment circuit of claim 1 whereinsaid gain adjustment module includes trim resistors and wherein aresistance of said trim resistors determines said first and secondsignal gains.
 7. The sensor module adjustment circuit of claim 6 whereinsaid signal preset module is a resistor trimming module that adjustssaid resistance.
 8. A sensor module adjustment circuit for a vehiclecontrol system, comprising: a vehicle device having a position betweenminimum and maximum positions, wherein said vehicle device is one of anaccelerator pedal, a brake pedal, a clutch pedal, or a throttle blade ofa vehicle; first and second position sensors that sense said position ofsaid device and that generate first and second position values,respectively; a sensor module that includes: a first signal conversionmodule that generates a first signal waveform based on said firstposition value, that varies a frequency of said first signal waveformbased on said first position value, and that includes a first gainmodule; a second signal conversion module that generates a second signalwaveform based on said second position value, that varies a duty cycleof said second signal waveform based on said second position value, andthat includes a second gain module; and a gain magnitude module thatcommunicates with said first and second gain modules and that determinesfirst and second signal gains of said first and second gain modules,respectively; and a signal preset module that communicates with saidgain magnitude module and that adjusts said first and second signalgains so that said first and second signal waveforms are equal to firstand second predetermined signal waveforms, respectively, when saidposition of said vehicle device is fixed.
 9. A method for adjusting asensor module, comprising: sensing a position of a device with a firstposition sensor, wherein said position of said device is between minimumand maximum positions and wherein said first position sensor generates afirst position value; sensing said position of said device with a secondposition sensor, wherein said second position sensor generates a secondposition value; generating a first signal waveform with a first signalconversion module based on said first position value; varying afrequency of said first signal waveform based on said first positionvalue; generating a second signal waveform with a second signalconversion module based on said second position value; varying a dutycycle of said second signal waveform based on said second positionvalue; adjusting a first signal gain of a first gain module in saidfirst signal conversion module and a second signal gain of a second gainmodule in said second signal conversion module so that said first andsecond signal waveforms are equal to first and second predeterminedsignal waveforms, respectively, when said position of said device isfixed.
 10. The method of claim 9 further comprising generating a singlesignal waveform based on said first and second signal waveforms.
 11. Themethod of claim 10 wherein a frequency of said single signal waveformcorresponds with said frequency of said first signal waveform and a dutycycle of said single signal waveform corresponds with said duty cycle ofsaid second signal waveform.
 12. The method of claim 10 furthercomprising: transmitting said single signal waveform to a control moduleon a conductor; and decoding said single signal waveform at said controlmodule to determine said first and second position values.
 13. Themethod of claim 12 further comprising scaling said first and secondposition values between position values that correspond to said firstand second predetermined signal waveforms and a position value that islearned during normal operations to determine said position of saiddevice.
 14. The method of claim 13 further comprising converting saidposition of said device into a normalized value that represents afraction of a range between said minimum and maximum positions of saiddevice.
 15. The method of claim 14 wherein said device is a throttleblade of a vehicle and wherein said control module determines saidnormalized value based on a measured position value, position valuesthat correspond to said first and second predetermined signal waveforms,a learned minimum position value, a maximum airflow position value, abreakout position value, and/or a breakout displacement value.
 16. Themethod of claim 9 further comprising: transmitting said first signalwaveform to a control module on a first conductor; transmitting saidsecond signal waveform to said control module on a second conductor; anddecoding said first and second signal waveforms at said control moduleto determine said first and second position values.
 17. The method ofclaim 16 further comprising scaling said first and second positionvalues between position values that correspond to said first and secondpredetermined signal waveforms and a position value that is learnedduring normal operations to determine said position of said device. 18.The method of claim 17 further comprising converting said position ofsaid device into a normalized value that represents a fraction of arange between said minimum and maximum positions of said device.
 19. Themethod of claim 18 wherein said device is a throttle blade of a vehicleand wherein said control module determines said normalized value basedon a measured position value, position values that correspond to saidfirst and second predetermined signal waveforms, a learned minimumposition value, a maximum airflow position value, a breakout positionvalue, and/or a breakout displacement value.
 20. The method of claim 9wherein said device is a throttle blade of a vehicle and wherein saidposition of said throttle blade is fixed at one of a maximum airflowposition, a breakout position, a minimum stop throttle position, or adefault throttle position while said signal preset module adjusts saidfirst and second signal gains.
 21. The method of claim 9 wherein saiddevice is one of an accelerator pedal, a brake pedal, a clutch pedal, ora throttle blade of a vehicle.
 22. The method of claim 9 wherein thesensor module includes a gain adjustment module that communicates withthe first and second gain modules, said gain adjustment module includestrim resistors, and a resistance of said trim resistors determines saidfirst and second signal gains.
 23. The method of claim 22 wherein aresistor trimming module adjusts said resistance.